From 333ed74689b8fca097574124fef7fa0e3d7f79d4 Mon Sep 17 00:00:00 2001
From: Will Deacon <will@kernel.org>
Date: Wed, 3 Jun 2020 12:16:37 +0100
Subject: [PATCH] scs: Report SCS usage in bytes rather than number of entries

Fix the SCS debug usage check so that we report the number of bytes
used, rather than the number of entries.

Fixes: 5bbaf9d1fcb9 ("scs: Add support for stack usage debugging")
Reported-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Will Deacon <will@kernel.org>
---
 kernel/scs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/scs.c b/kernel/scs.c
index 222a7a9ad543..5d4d9bbdec36 100644
--- a/kernel/scs.c
+++ b/kernel/scs.c
@@ -74,7 +74,7 @@ static void scs_check_usage(struct task_struct *tsk)
 	for (p = task_scs(tsk); p < __scs_magic(tsk); ++p) {
 		if (!READ_ONCE_NOCHECK(*p))
 			break;
-		used++;
+		used += sizeof(*p);
 	}
 
 	while (used > curr) {